11-6
CONTROL SYSTEM
SM PNXDCI 1-A.1 GB
11.7.4 Compressor over Current Protection
11.7.5 Heat Sink Over Heating Protection (NA for DCI 25 and 35)
HST
HST Trend
Decreasing No Change Increasing
HST > 90
SC SC SC
85 < HST ≤ 90 D1 D2 D2
82 < HST ≤ 85 SR D1 D2
80 < HST ≤ 82 SR SR D1
78 < HST ≤ 80 Norm Norm SR
HST ≤ 78 Normal
11.7.6 Outdoor Coil Deicing Protection
11.7.6.1 Deicing Starting Conditions
Deicing operation will start when either one of the following conditions exist:
• Case 1: OCT < - DST – AND TLD > DI
• Case 2: OCT < OAT – 12 AND TLD > 30 minutes.
• Case 3: OCT < - AND TLD > 75 minutes
• OCT is Invalid AND OCT < 0
• Compressor ON Time > 15 minutes
OCT – Outdoor Coil Temperature
OAT – Outdoor Air Temperature
TLD – Time from Last Deicing
DI – Deicing Interval (Time Interval Between Two Deicing)
DST – Deicing static threshold (Temperature)
Where DST is defined as:
When OAT > 0 or OAT is invalid, then DST = 8
When OAT ≤ 0 then DST = round down (- 0.7*OAT)+8
Normal
Stop-Rise
HzDown1
HzDown2
Stop-Compresor
CCROC1
CCROC2
CCROC3
CCROC4
CCR
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